One Button Duel

Includes a local multiplayer mode and a peer-to-peer online multiplayer mode. Note that the online mode is disabled by default. To play online, click the "Enable Online" button at the top, register an ID, and then connect to your opponent's ID. I didn't test it out that extensively, so if you run into any issues let me know!

Rules:

If neither player let go before passing, it's a tie.

If one player let go before passing, that player wins.

If both players let go before passing, the winner is decided by speed.If speeds are the same, it's a tie.

Hmm, sounds like the connection happened before the cartridge finished GPIO setup. I'll try to find some time for a bugfix, but in the meantime if you wait a few seconds after the game has started to hit "Enable Online" you might have better luck getting it to work.